1. Field of the Invention
The present invention relates to a music reproducing system having a function of accurately extracting a rhythm component of musical data upon reproduction thereof and changing a display figure of a character based on the extracted rhythm component.
2. Description of the Related Art
There are many personal computers and video game apparatuses provided with a device for reading a CD-ROM storing program codes and various data. Most of them can read a music CD storing musical data and reproduce music from the musical data.
Further, there have recently appeared video game apparatuses with a music reproducing function, wherein a character in a CG (computer graphic) image is displayed on a display screen and dances autonomously or via an external operation to the accompaniment of a rhythm of reproduced music, so that a game player can enjoy not only the reproduced music itself, but also visually.
For example, JP-A-10-99546 introduces a video dance game apparatus, wherein at least two dance players, i.e. characters, are displayed on a display screen, and a dance contest is carried out depending on a time difference between the timing at which dance technique data of each character is read out via an external operation and the timing at which beat information (information forming the basis of a rhythm of music) contained in dance music is produced. This video dance game apparatus can use only dance music as music (musical data) for extracting the beat therefrom.
In the foregoing video game apparatuses, beat extraction is implemented using a filter on the assumption that reproduced music is dance music so that the frequencies of an instrument beating a rhythm, i.e. the beat generation frequencies, are concentrated to a low frequency band, such as a drum sound. However, there is such dance music wherein the beat generation frequencies do not necessarily fall within the low frequency band. In this event, the accurate beat can not be extracted, thus resulting in lack of objectivity of a dance contest.
Further, in the conventional technique, it is not possible to accurately analyze the rhythm of music, other than dance music, reproduced from a commercial music CD wherein a variety of instruments beat the rhythm, for reflection upon a display figure of a character.